[Mediawiki-l] building a replica/backup media wiki

Daniel Friesen lists at nadir-seen-fire.com
Thu Mar 15 00:04:04 UTC 2012


On Wed, 14 Mar 2012 14:51:06 -0800, Joseph Spenner <joseph85750 at yahoo.com>  
wrote:

> I'm currently trying to run a nightly backup/copy of my production media  
> wiki to a "read only" copy on another system.  I wrote a script to do  
> everything through ssh:
>
> ----
>
> #!/usr/bin/ksh
>
> scripts=/scripts
>
> mysqldump --opt wikidb -u root -psomePass > $scripts/wikidb.sql
>
> scp $scripts/wikidb.sql 10.4.3.1:tmp || exit
>
> sleep 3
>
> ssh 10.4.3.1 '/usr/bin/mysql -u root -psomePass wikidb < tmp/wikidb.sql'  
> || exit
>
> echo replica wiki database updated
>
> echo syncing attachments and files
>
> rsync --delete -avz -e ssh /var/www/htdocs/wiki/images  
> root at 10.4.3.1:/var/www/htdocs/wiki
>
> ----
>
> My copy/replica has an entry in the LocalSettings.php to make it a  
> read-only wiki:
>
> $wgReadOnly = 'Read Only';
>
> It works great.
>
> However, when I access the replica after a period of time, it's VERY  
> slow/sluggish.  If I edit the LocalSettings.php file and disable the  
> 'read only' line, it's lightning fast again.  If I then change it back  
> to 'read only', it's still fast but slows down over the course of the  
> night.
>
> The only way around this was to make a little script which places a  
> normal edit-able LocalSettings.php file into place, then does a wget to  
> one of the wiki pages, then copies the 'read only' version of the  
> LocalSettings.php file back into place.  After I run the script, it's  
> fast again.
>
> Anyone know why this slowness occurs?  I've tested the mysql response  
> time via command line while the wiki is slow, and the mysql is still  
> fast.  It's some interaction between apache and mysql which causes this  
> replica to slow down.  If I try to access a 'non wiki' document (ie:  
> some file on the webserver) it does not have any latency.
>
> Any ideas/help would be great.
>
> Thanks!

If you turn off read only but set $wgMainCacheType = CACHE_NONE; does your  
wiki feel as slow as it does overnight?

-- 
~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name]



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